Car and Motorcycle Horns
Horns are used on all sorts of vehicles from motorcycles, cars, trucks, utility vehicles and so on. They are a very simple device and come in couple of styles. These include Diaphragm, Horn, and Air Horn styles, some even play music like La Cucaracha, or Dixie like in The Dukes of Hazzard County.
Wiring up an existing horn is pretty simple, and depending on your application you may want to use a relay to hook it all up. More on the shortly. The Introduction to Automotive Relays can also help with fresh installs.
How to Wire a Horn
I'll be skipping how a horn works, this is more how to hook them up. One common question in doing so is How Much Current Does It Draw? Well I have collected a list of common aftermarket horns (both Electro-mechanical and Air) so you can figure out the first step. In general most new cars and trucks (even motorcycles) have relays driving the horns from the steering wheel so replacing an existing horn is pretty easy. The only thing you need to worry about in that case is current draw.
Here is the big list of horns I mentioned, it's broken down by manufacturer and by horn type -
Horn Switch Grounding Relay Wiring
In the example above the horn circuit is closed by the horn switch completing the circuit to ground. This is a very common steering wheel wiring schematic. Usually their will be one wire coming into the horn button and to close the circuit the switch grounds that wire. This is not always the case, but a very common one. You may ask what size fuse or wire should I use? Well depends on your horn(s) current ratings start with a fuse at that or just larger. For wiring size of power to your horn use this wire size calculator. (Note: The control terminals 85 or 86 which can be thin 18 gauge wire). If you are wiring up an Air horn it would look the same, the Air compressor positive wire would come from terminal 87 (just like above) and the ground wire from the compressor would tie to a bolt on the chassis.
Car Horns and You Conclusion
So we have shown a couple of common examples how to wire up your horn(s). Doesn't matter if a boat, car, motorcycle or RV. Some smaller vehicles (motorcycles as an example) may not have a horn relay. It's important to make sure the current draw is not too high for the switch, fuse or wiring if that's the case. The relay is a good addition to the mix if you don't have one switching your horns.
Don't expect to use an Air Horn without a relay and appropriate wire and fuse changes
Most horns sound better when used in pairs one High Tone, one Low Tone
If your horn has only one connection, the mounting bracket will be the GROUND
Some of the Manufacturer links above (or from their main web sites) have sound samples of the horns
Horn Amperage List
The current draw is in Amps for EACH / SINGLE / ONE horn unless otherwise specified! So if you are asking - 'How many amps is this horn' this list might be helpful.
Hella Horn PDF Download
Hella Super Tone Horns 5.5 Amp
Hella Sharpe Tone Horns 2.5 Amp
Hella Trumpet Horn 6 Amp Each
Hella Universal Disc Horn 6 Amp
Hella Twin Tone Air Horn Kit 20 Amp
Hella Triple Tone Air Horn Kit 20 Amp
Wolo Air Horns
Wolo Air Horns
Wolo Model 400 Small Plastic Series Dual Air Horns 16 Amp
Wolo Model 400 Larger Metal Dual Air Horns 18 Amp
Wolo Model 419 Bad Boy Series 16 Amp
Seger 45C Series 5 Amp
Seger 50F Series 5 Amp
Seger 55B Series 3.5 Amp
Seger 60 Series 6 Amp
Seger 62 Series 6 Amp
Seger 65 Series 6 Amp
Seger Air Horns
Seger 58KH Series 15-20 Amp
Seger 80KH - 82KH 21 Amp
Seger 82KM - 82KH 26 Amp
FiammFiamm Catalog PDF
Fiamm Electro Mechanical
Fiamm AM-80S (includes Freeway Blaster) Series 6 Amp
Fiamm El Grande Twin Electric Horns 12 Amp (Pair)
Fiamm HK-9 Series Disc 5 Amps
Fiamm ATV Horn 8 Amp
Fiamm UTV Horn 12 Amp (Pair)
Fiamm 518 Series Hidden Horn 5 Amp
Fiamm 519 Series Hidden Horn 6 Amp
Fiamm Airtone Stainless Steel 6 Amp
Fiamm Airtone Stainless Steel Twin 12 Amp (Pair)
Fiamm Air Horns
Ultimate Blast 20 Amp
**Most have no current listed, plan on 20 Amp
StebelStebel Catalog PDF
Stebel HF80 Series 4.5 Amp
Stebel TM80 Series 5.5 Amp
Stebel TM80 Magnum Series 6 Amp
Stebel Air Horns
Stebel Natilus Series 18 Amps
Stebel GP Series 16 Amp
Stebel VM 2 Series 18 Amp
Stebel AM 2 Series 18 Amp
Stebel Nautical Series NM2 18 Amp
Stebel BP Series 18 Amp
Stebel Musical MP Series 18 Amp
For Unlisted and OEM horns I would ASS-U-ME a 6 AMP rating for EACH horn.
Feedback or missing info please click the spark plug in the very upper right corner and send me a message!
Horn Wiring Examples
Wiring up horns are pretty easy since your car likely has one already. Some cars have simple wiring that does not use a relay but most have the relay. Start with a wiring diagram of your car (or Motorcycle, RV, etc.) and see how they hook it up. If you can't find a wiring diagram you can see if it has a relay by unplugging the horn and listening for a mechanical clicking when you push the horn button.
One of the most important things is making sure your wiring and fuse can handle the current draw for your horns (or Air Compressor for your Air Horns). Find the Horn fuse and check the amperage rating. It's likely to be 10 Amps or greater. Bigger horns (generally) draw more power. The largest draw seems to be for Air horns.
Their are basically 2 types of horns we will talk about, Electro-Mechanical and Air horns. Electro-Mechanical are just the standard style horn, diaphragm, etc. Air horns are ones with a small air compressor.
Both Air horns and Electro-Mechanical horns are hooked up basically the same way, however Air Horns typically require a lot more current, almost 2x of the simple electrical brothers. It's very important to ensure your wiring and fuse capacity is correct. Wiring capacity for horns can afford a bit of leaning to the smaller side since the Horn is intermittently used... If that's not the case stick with recommended wiring gauge, especially for the larger current drawing Air Horn types.
Again don't forget that typically 2 horns are used on cars to provide a pleasing tone, one horn is a LOW tone and the other is a HIGH tone. Just make sure you check the charts for the current draw.
Below are 2 images with typical wiring diagrams for hooking up you horns. Air horns can be interchanged with Electro-mechanical horn types but be aware you may need larger fuse, wire and the use of a relay. In all cases it's better to use the relay to switch the high current draw of the horns unless you are using small low powered units, for example my Sunbeam Tiger does not use a horn relay, but likely should... Ah British wiring ;)
Common Automotive Horns
Below is a chart of common Automotive horns. They should look similar to something on your car, motorcycle, or boat.
Nothing magical, some OEM horns may have a different shape but almost all are based on one of the pictures below.
Some things to note -
If you horn has only ONE terminal the mounting bracket will be your Ground connection. So the single terminal horn Positive lead will go to the connector, the the chassis ground will complete the circuit.
If your horn has 2 terminals you may ask which is Positive and which is Negative? Well if they are marked with polarity or a red (+) and a black (-) that is how you hook them up. If their are no markings you can generally hook them up either way. This applies to either Horn shaped (top row) or Diaphragm (middle row) horns.
For Air Horns you will need to connect them up in a similar way, most Air Compressors for air horns have a marked Positive (+) and Negative (-) terminal. In the case where one might exist, the mounting bracket and case are likely the ground.